The present invention is directed to silicone macromers, which can be made by the organolithiation of an organosilicon cyclic, the end capping of the resulting lithiated organosilicon polymer with a silicon hydride followed by the addition onto the silicon hydride of an aliphatically unsaturated monohydric phenol. More particularly, the present invention relates to the synthesis of thermoplastic flame retardant silicone-polyphenylene ether graft copolymers by oxidatively coupling a monohydric phenol with the aforementioned monohydric phenol end capped silicone macromer.
Prior to the present invention, as shown by Bostik, U.S. Pat. No. 3,522,326, graft copolymers of polyphenylene ether were made by metallating a polyphenylene ether with an organoalkali metal which was reacted with an anionically polymerizable monomer. Organopolysiloxane-polyphenylene ether block copolymers are shown by Kranz, U.S. Pat. No. 3,668,273, involving the reaction between hydroxy terminated polyphenylene ether segments with amine terminated polydiorganosiloxane segments. Another silicone-polyarylene ether block copolymer is shown by Shea, et al, U.S. Pat. No. 4,814,392, which can be made by effecting reaction between an amine terminated polydiorganosiloxane and anhydride functionalized polyarylene ether.
Polyphenylene ether graft copolymers are shown by Chalk et al, Journal of Polymer Science Vol. 7, 2537-2545, p 7345-742 (1969). An investigation of the viscoelastic properties of polyphenylene ethers, and 2-methyl-6-alkyl-substituted polymers is shown by Eisenberg et al Macromolecules 5, p. 676-682 (1972). Polymerization of polydimethylsiloxane macromers with small monomers to make graft copolymers is shown by Cameron et al, Polymer, 1985, Vol. 26, March, p. 437-442. In addition, certain silicon containing graft copolymers, useful as gas-separation membranes are shown by JP61,252,214.